A client apparatus in accordance with the present invention includes a contents list request transmitting means 401 for transmitting a request of a media server apparatus 101 to transmit a contents list which is a list of metadata of contents, a contents list receiving means 402 for receiving the contents list from the media server apparatus 101, an item list storing means 403 for storing the contents list and an item list having listed items each of which is described as metadata, an item list transmitting means 404 for transmitting the item list to a monitor server apparatus 102, a key input means 405 for receiving a key input, an input key transmitting means 406 for transmitting the key input to the monitor server apparatus 102, and an identification information receiving means 407 for receiving identification information making it possible to uniquely identify each item included in the item list.